rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-....: (1 ticks this GP) idle=174c/1/0x4000000000000000 softirq=16009/16009 fqs=5 rcu: hardirqs softirqs csw/system rcu: number: 0 0 0 rcu: cputime: 0 0 0 ==> 38980(ms) rcu: (detected by 0, t=10502 jiffies, g=10937, q=909 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5823 Comm: syz-executor Not tainted 6.15.0-rc6-syzkaller-00160-gc39b1bb5bc6d #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:hlock_class kernel/locking/lockdep.c:233 [inline] RIP: 0010:mark_lock+0x3c/0x190 kernel/locking/lockdep.c:4732 Code: 00 03 00 83 f9 01 bb 09 00 00 00 83 db 00 83 fa 08 0f 45 da bd 01 00 00 00 89 d9 d3 e5 25 ff 1f 00 00 48 0f a3 05 c4 b7 de 11 <73> 10 48 69 c0 c8 00 00 00 48 8d 88 e0 26 1e 93 eb 48 83 3d db 46 RSP: 0018:ffffc90000a08aa8 EFLAGS: 00000047 RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008 RDX: 0000000000000008 RSI: ffff88802d50a990 RDI: ffff88802d509e00 RBP: 0000000000000100 R08: 0000000000000000 R09: 0000000000080000 R10: 0000000000000000 R11: ffffffff84beb54a R12: 0000000000000000 R13: 0000000000000000 R14: ffff88802d50a9b0 R15: ffff88802d50a990 FS: 0000000000000000(0000) GS:ffff8881261c7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000500 CR3: 000000007ab40000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_usage kernel/locking/lockdep.c:4675 [inline] __lock_acquire+0x68c/0xd20 kernel/locking/lockdep.c:5189 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__folio_rmap_sanity_checks+0x197/0x6e0 arch/x86/include/asm/jump_label.h:-1 Code: 01 0f 85 b9 02 00 00 4d 8d 2c 2f 4d 8d 24 2f 49 83 c4 c0 0f 1f 44 00 00 e8 56 d8 ae ff 44 89 f5 49 bd 00 00 00 00 00 fc ff df <44> 8b 74 24 04 4c 39 e3 0f 85 98 02 00 00 e8 36 d8 ae ff 44 89 f7 RSP: 0018:ffffc900044e7350 EFLAGS: 00000293 RAX: ffffffff8211199a RBX: ffffea0001896500 RCX: ffff88802d509e00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffea0001896507 R09: 1ffffd4000312ca0 R10: dffffc0000000000 R11: fffff94000312ca1 R12: ffffea0001896500 R13: dffffc0000000000 R14: 0000000000000001 R15: ffffea0001896500 __folio_remove_rmap mm/rmap.c:1694 [inline] folio_remove_rmap_ptes+0x3b/0xaf0 mm/rmap.c:1804 zap_present_folio_ptes mm/memory.c:1525 [inline] zap_present_ptes mm/memory.c:1586 [inline] do_zap_pte_range mm/memory.c:1687 [inline] zap_pte_range mm/memory.c:1731 [inline] zap_pmd_range mm/memory.c:1823 [inline] zap_pud_range mm/memory.c:1852 [inline] zap_p4d_range mm/memory.c:1873 [inline] unmap_page_range+0x17f2/0x4210 mm/memory.c:1894 unmap_vmas+0x25d/0x3c0 mm/memory.c:1984 exit_mmap+0x245/0xba0 mm/mmap.c:1284 __mmput+0x118/0x420 kernel/fork.c:1379 exit_mm+0x1da/0x2c0 kernel/exit.c:589 do_exit+0x859/0x2550 kernel/exit.c:940 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x8b/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f04c0d84b93 Code: Unable to access opcode bytes at 0x7f04c0d84b69. RSP: 002b:00007ffc18413688 EFLAGS: 00000202 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 00000000000016c4 RCX: 00007f04c0d84b93 RDX: 0000000040000000 RSI: 00007ffc1841369c RDI: 00000000ffffffff RBP: 00007ffc1841369c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008 R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 3898 jiffies! g10937 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 3490 Comm: kworker/u8:8 Not tainted 6.15.0-rc6-syzkaller-00160-gc39b1bb5bc6d #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xe69/0x11c0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 80 6d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 2b 69 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 10 69 0b RSP: 0018:ffffc9000c5af700 EFLAGS: 00000293 RAX: ffffffff81b488e0 RBX: ffff8880b883ad40 RCX: ffff888030ff8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000c5af860 R08: ffffffff8f7efe77 R09: 1ffffffff1efdfce R10: dffffc0000000000 R11: fffffbfff1efdfcf R12: 1ffff11017127e99 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b893f4c8 FS: 0000000000000000(0000) GS:ffff8881260c7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c36be68 CR3: 000000000dd38000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2757 [inline] text_poke_bp_batch+0x319/0x940 arch/x86/kernel/alternative.c:2967 text_poke_flush arch/x86/kernel/alternative.c:3158 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:3165 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245